It wasn’t a fair fight. 24 trillion gallons of water does not fit into 627 square miles of Texas landscape. I have read and have heard several discussions concerning the ability of the Houston area to absorb the water dumped on the area during the days hurricane Harvey hovered over Houston and was curious,

how much water can an area the size of Houston handle?

And, more interestingly,

how much grassland would be needed to absorb a hurricane the size of hurricane Harvey?

Using estimated rainfall information provided by news outlets (Washington Post, NPR) and a water absorption study published in the Farmer’s Magazine in 1861, what are the numbers? The absorption study assumes starting with dry land and the average absorption numbers calculated in the study. Using high and low rainfall estimates of 9 and 24 trillion gallons and absorption levels of 4, 6, 9, and 12 inches this is what I found.

It would require an area from 104 to 829 times the size of Houston to absorb the high and low waterfall estimates of Hurricane Harvey.

If Harvey had covered the state Texas, on the low end Texas would be ok.

On the high end even an area the size of the state of Texas could not handle all the rain. It is hard to conceive the amount of rain which hit the area but is easy to understand why the extreme level of flooding occurred in the area.

How much water can an Acre of dry land absorb? Volume depends on the depth of absorption.

inches

tons of water

gallons of water

4

273

72118

6

408

107781

9

543

143444

12

816

215562

Total water converted to gallon/tons. Acres required to absorb the water, depth of absorption.

gallons

4 inches

6 inches

9 inches

12 inches

low estimate

9 trillion

332,786,039

222,673,011

167,312,318

111,336,506

high estimate

24 trillion

124,794,765

83,502,379

62,742,119

41,751,190

Square miles required to absorb hurricane Harvey.

gallons

4 inches

6 inches

9 inches

12 inches

low estimate

9 trillion

194,992

130,472

98,035

65,236

high estimate

24 trillion

519,978

347,927

261,425

173,963

Houston is 627 Square miles. How many Houstons would it take to handle Harvey?.